Automatic telephone system



APPLICATION FILED AUGIG. 1920.

Patented Nov. 21, 19220.

2 SHEETS-SHEET 1- E. JACOBSEN.

AUTOMATIC TELEPHONE SY'STEM.

APPLICATION FILED AUG. 6, 1920.

Patented Nov. 21, 1922.,

SHEETS-SHtET 2.

units s s.-

ear-ear oieeice.

EMIL JACOBSEN, PORT WASHINGTON, NEW YORK, ASSIGNOR TO AUTOMATIC ELEC- TRIO COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Original application filed March 25, 1918, Serial No. 224,429. Patent No. 1,349,381, dated August 10,

i 1920. Divided and this application filed August 6, 1920. Serial No. 402,502.

To all whom it may concern:

Be it'known that I, EMI1. JAcoBsEN, a citizen of the United States of America, and a resident of Port \Vashington, Nassau County, New York, have invented certain new and useful Improvements in Automatic Telephone Systems, of which the following is a specification.

This application is a division of my copending application Serial #224,429, filed March 25, 1918, Patent No. 1,349,381, granted August 10, 1920. My invention relates in general to an automatic telephone systern and more specifically to an automatic rotary connector switch of improved type. Connector switches of the rotary type have in the past been provided with double wipers, and the test contacts of the last trunk line in each group have been strapped together to stop the automatic rotation of the switch and give the calling man a busy signal.

In my improved circuit, however, I have so arranged the test contacts-that all except the last of the test contacts of a group are shorted and the last set of test contacts are left open, andhave revised the test circuits so that the switch will rotate past busy trunks which are connected together and will stop and give a busy signal when it meets a busy trunk whose test contacts are not connected.

In the drawings, I have shown an established connection between a calling subscriber A (Fig. 1) and a called subscriber B, (Fig. 2) which connection is established through the medium of a line switch C, selector E and a connector switch H, which connector has certain other improvements which will be pointed out.

The substations A and B are of the usual common battery type comprising the usual transmitter 2, receiver 3, call signal 5 and a calling device CD of well known type for interrupting the line circuit to send impulses.

The line switch Cis of a well known rotary type'comprising a line relay 6, switching relay 7 and rotary magnet 8., The selector E is of the well known Keith-Erickson twowire type in which the side switch has been omitted and the relays are controlled over the two sides of a calling line in series.

The connector switch H (Fig. 2) is also of the Keith-Erickson type in which the relays are. controlled over two sides of a callmg l me in series to establish a connection and 1n which the release is controlled by either the calling or the called man, that is, the last one to hang up. I will describe the operation in detail when the subscriber A calls subscriber B by referring to the drawings.

WVhen the receiver at substation A is removed, the closure of springs 4 by the receiver hook closes a circuit for line relay 6, which in turn closes a circuit for relay 7 and magnet 8 in series. Relay 7 is however short circuited by ground from the private wiper 10 and magnet 8 is operated by said ground to find an idle trunk, at which time relay 7 1s no'longer short circuited and energizes to extend the line'circuit to selector E through the springs 12 and 13 thereby closing a circuit for the line relay 1 1 of selector E. The line relay 14, upon energizing, closes a circuit for slow release relay 17 in the usual manner to connect ground to the release trunk to maintain the relay 7 of switch C energize-d and to make thetrunk line busy at contact 70. The first series of impulses from the subscriber A operates the line relay 14 in the usual manner to operate the vertical magnet 71, thereby raising the wipers 72, 73 and 74 to a desired level of the bank. The ofi' normal springs 75 and 76 close to prepare certain circuits as soon as the switch leaves normal. The slow relay 77 energizes during the operation of magnet 71 and closes a circuit for relay 78 at springs 79 and 80. Relay 78 energizes to prepare the circuit of magnet 81- at springs 82 and locks itselt through springs 84, springs .83, springs 89, springs 76 and through its own winding to battery. As soon asrelay 77 deenergizes after the vertical impulses, the circuit for magnet 81 is completed at springs 79 and 85. Magnet 81 operates to step the wipers one step and opens the circuit of relay 78 at springs 89, relay 78 therefore deenergizes and opens the circuit of magnet 81. If the connected trunk is busy, ground from wiper 74 will again energize relay 78 through springs 86 and 87 and sprin 's 89 and 76, so that the rotary magnet will again operate. This operation of relay 78 and magnet 81 continues until an idle trunk is found, at which time relay 88 which has heretofore been short circuited, operates in series with relay 78 todisconnect the relays of the switch E from the line circuit and extend the line circuit to the selected trunk, from which a ground is fed back a short time later over the private wiper 7 4 to hold the relays 7 and 88 energized. The energization of relay 88 at this time closes a circuit for the line relay 15 of connectorH, which relay immediately energizes over the line circuit and closes a circuit for the slow release relay 16. Belay 16 energizes to provide a holding circuit for relay 7 of line switch C and relay 88 of selector E through springs 18, opens the c rcuit of the release magnet 19 at one polnt and prepares a circuit for the vertical magnet 20 and slow relay 21. The subscriber now operates the springs CD to interrupt the circuit of relay 15 a number of times. Each time relay 15 deenergizes, a circuit is closed from ground through springs 22 and 23, springs 24, springs 25 and 26, and magnet 20 and relay 21 to battery. Magnet 20 therefore operates to raise the wipers 27, 28, 29 and 30 to some level of the connector banks. The initial circuit for energizing the vertical magnet is opened at springs 25 and 26 as soon as the switch leaves normal position but a new circuit is closed through springs 25 and 31, springs 32 and 33 and through magnet 20 and relay 21 to battery. As soon as the first series of impulses cease,

relay 21 deenergizes to open the circuit of magnet 20 and close a point in the circuit of rotary magnet 34. When the line relay 15 operates for the next series of impulses-it operates the magnet 34 over a circuit from ground through springs 22 and 23, springs 24, springs 25 and 31, springs-32 and 35, slow relay 36, springs 37, s rings 38 and 39, and magnet 34 to battery. agnet 34 therefore operates to rotate the wipers 27-30 inclusive to a set of contacts to which the desired line is connected. The relay 36 remains energized during the operation of magnet 34 and for a short interval after the impulses to said magnet cease, so that the test wiper 29 is held in connection with the relay 40 for an instant. If the called line is busy, a ground will be present at said Wiper and relay 40 will energlze to prepare a locking circuit for itself which is closed when relay 36 deenergizes and extends from ground through springs 41 and 42 of relay 16, springs 43 and 44, springs 45 and 46, springs 47, and relay 40 to battery. Relay 40 also disconnects the rotary magnet at springs 37 and transmits a busy signal to the calling subscriber, who may then release the connection in the usual manner by restoring his receiver. Relays 15 and 16 will then deenergize and close a circuit for the release magnet from ground through springs 41 and 48, springs 49 and 50, and magnet 19 to battery.

Assumin the called line to be idle when connection is extended thereto then relay 40 will not be energized and when relay 36 falls back a circuit will be closed for the lower winding of relay 51 extending from ground through springs 41 and 42, springs 43 and 44, springs 45 and 52, windin of said relay, springs 53, springs 54 and 55, wiper 29, and cut-ofi' winding of switch C to battery. Relay 51 therefore energizes and locks itself toground through springs 56. The relay 51 also opens the circuitfor its lower winding and connects ground direct to the wiper 29 through springs 57 and 55, while the springs 58 close the talking circuit at one point. The springs 49 open another point in the circuit of release magnet 19. The closure of springs 58 connects interrupted generator to the called line in series with ring cut-off relay 59 which is energized when the called subscriber answers to cut off the ringing current, locks itself energized, and cuts the talking circuit through at springs 60 and 61 and connects ground to the upper one of the springs 49 through springs 62. As soon as the talking circuit is cut through by springs 60 and 61, the back bridge relay 63 is energized in series with the called line to reverse battery to the calling line for any desired purpose. Conversation may now proceed over the heavy conductors shown. When conversation is completed, the connection is released in the following manner.. Should the calling subscriber restore his receiver first, the

line relay 15 will deenergize and open the circuit of slow release relay 16. Relay 16 will also deenergize to remove ground from the holding circuit of line switch C at springs 18, opens the springs 41 and 42, and closes springs 41 and 48. The springs 41 and 42 do not open until springs 22 and 23 come into contact so that ground through springs 22 and 23, and springs 64 replaces the ground through springs 41 and 42 in the holding circuit of relay 51 which therefore remains energized to hold the circuit of the release magnet 19 open at springs 49. l/Vhen the called subscriber hangs up, relay 63 deenergizes and opens the circuit of relay 51 at springs 64. elay 51 will therefore deenergize, close the circuit of the release magnet at-springs 49, and open the holding circuit of ring cut-01f relay 59 at spring 39. The connector H will be released therefore and restored to normal position. Itwill be noted that while the switch H is being held by the called subscriber and after the calling subscriber has restored his receiver that the switch H is accessible to another calling subscriber. That is, when relays 15 and 16 deenergize, the guarding ground for the said connector from springs 18 to the test contact is removed. Now should another subscriber similar to A seize the connector H to extend another call, means 1S provided for releasing said switch H from the called subscribers line. This result is accomplished as follows: When such a connection is established, a circuit is closed for line relay 15 in series with this secondline in the same manner as when subscriber A called. Relay 15, upon energizing, opens the springs 22 and 23 to open the holding-circuit of relay 51. Relay 51 deenergizes and a circuit is then closed for release magnet 19 extending from ground through springs 62, springs 49, springs 50 and said magnet to battery. The switch H is therefore released regardless of the fact that a called subscriber is holding the same and may be used by the second calling man to call another party. This connector switch is also provided with means for automatically selecting any one of a group of contacts in an im-' proved manner. Certain levels of the bank in this switch may be divided up into groups, that is, the switch may he stepped to a certain level and may then rotate automatically over a number of trunks to pick out an idle one. At 90, 91 and 92 is shown a part of another level showing ,one group of the private contacts of such level. In this case all but the last of such pairs of private contacts will be strapped together as at 90 and 91 while the last pair are left open. Now if the last switch is directed to the contact 90 and it said contact is idle, the switch will cut through in the same manner as'explained; but, if such contact he busy and a ground is connected to the lower contact then this ground will pass through wiper 28, through springs 94. springs 95, springs 96, and through relays 93 and 21 to battery. Relay 93 will therefore energize to close a circuit for rotary magnet 34: at springs 96 to rotate the wipers onto the next set of contacts 91. Rotary magnet 34, upon energizing, opens the circuit of relay 93 at springs 96 so that relay 93 will again deenergize and the operation may proceed with regard to contacts 91, where the same operation will occur. If the first two pairs of contacts are busy and the switch rotates to contacts 92 then the switch will stop and test in the same manner as when calling substation R and it this is also busy then a busy signal will be given from relay 40 in the usual manner.

It will be seen therefore that I have provided an improved and efficient manner of holding a connector switch selectable and releasable while being held by a previously called party and that said switch also operates in an improved manner to select one of a group oi trunks automatically.

What I claim as my invention is:

1. ln a telephone system, an automatic switch, lines accessible tosaid switch divided into groups, a pair of test contacts for each line, a connection between the contacts of each pair except the pairs which are associated with the last lines of said groups, two test wipers for said switch, means for making certain of said lines busy by establishing a guarding potential at one of the test contacts associated therewith, means for operating said switch to rotate said test wipers into engagement with the pair of test contacts associated with the first line in one of said groups, and means in said switch controlled over said wipers for causing said switch to rot-ate another step in case the said first line is busy.

2. In a telephone system, an automaticswitch, lines of difi'erent character accessible to said switch, a pair of test contacts for each line, a pair of test wipers for said switch, means for operating said switch to test the said lines via said wipers and test contacts, means for making said lines busy, a relay controlled over one wiper to transmit a busy signal to the calling subscriber if a called line of one character is busy, another relay controlled over said wiper to switch the connection through to the said called line if the line is idle, and a relay controlled over the other wiper for causing the continued rotation of the switch when lines of the other'character are tested and found busy.

3. In a telephone system, an automatic switch, lines accessible to said switch, a pair of test contacts for each lineand a pair of cooperating test wipers for said switch. means for operating said switch to test said lines via said wipers and contacts, means for making'said lines busy, a relay for giving a busy signal to the calling line, and a relay for switching the connection through to an idle line, a slow-acting relay for switching said two relays successively into connection with one of said wipers when an idle line is tested, and another relay connected to the other of said wipers for causing the automatic rotation of said switch when busy lines are tested.

4. In a telephone system, an automatic switch, lines of different character accessible to said switch, a pair of test contacts for each line, the test contacts of all lines of one character being short circuited, means for making said lines busy, means for operating said switch to test said lines, means for automatically rotating said switch in search of an idle line when a line of the character having short circuited test contacts is tested and found busy, and means for giving a busy signal tothe calling subscriberwhen a line of the other character is tested and found busy.

5. In a telephone system, a group of lines, an automatic switch, a test contact and an auxiliarytest contact for each line, a conwiper for said switch, means for placing a guarding potential on the test contacts associated with busy lines, means for operating said switch to cause said wipers to engage the contacts associated with the first of said lines, and means controlled over said auxiliary test wiper for continuing the operation of said switch jn case the first line is busy.

with busy lines, subscriber controlled actuating means for directively operating said switch to bring said wipers into engagement with the contacts associated with the first of said lines, and circuit arrangements for placin said actuating means under control of sai auxiliary test Wiper to automatically operate said switch in case the first line is busy.

7. In a telephone system, a group of lines, an automatic switch, a test contact and an auxiliary test contact for each line, a connection between each test contact except the last and the associated auxiliary test contact, a test wiper and an auxiliary test wiper for said. switch, means for placing a guarding potential on the test contacts associated with busy lines, a motor magnet in said switch controlled by a calling subscriber to cause said wipers to engage the contacts associated with the first of said lines, and circuit arrangements for placing sai-d motor magnet under control of said auxiliary test wiper to automatically move said wipers into engagement with the next set of contacts in case the first line is busy.

8. In a telephone system, a group of lines, an automatic switch, a test contact and an auxiliary test contact for each line, a connection etween each test contact except the last and the associated auxiliary test contact, a test wiper and an auxiliary test wiper for said switch, means for placing a guard-' ing potential on the test contacts associated with busy lines, means for operating said switch to cause said wipers to engage the contacts associated with the first of said lines, means controlled over said auxiliary test wiper for continuing the operation of said switch in case the first line is busy, a test relay controlled over said test wiper, and a wiper connecting relay controlled by said test relay and adapted to operate when an idle line is found.

'erating sai 9. In a tele hone system a rotary connector, indivi ual lines and grouped lines accessible to said connector, a test contact and an auxiliary test contact for each line,

the test' contacts of individual lines being insulated from their associated auxiliary test contacts and the test contact of the last line in each group of lines bein likewise insulated from its associated auxiliary test contact, a conductive connection between ever other test contact and its associated auxi iary test contact, a test wiper and an auxiliary test-wiper in said connector, means for operating said connector to connect its wipers with the contacts of any desired individual line or with the contacts of the first line in any group of lines, means controlled over the said test wipers for automatically operating said connector to select an idle line if a busy grouped line is connected with, and means for givin the callmg subscriber a busy signal if a usy indi- Vi ual line is connected with or if a grouped line is connected with at a time when all the lines in the group are busy.

10. In a telephone system, a rotary connector having a test wiper and an auxiliary test wiper, lines accessible to said connector, a test contact for each line and an auxiliary test contact 'for each line, a motor magnet in said connector, a stepping relay for op,- erating said magnet, and circuit connections for operating said stepping relay by way of said auxiliary test wiper and the auxiliary test contacts of busy called lines.

11. In a telephone system, a rotary connector, having a test w1per and an auxiliary test wiper, lines accessible to said connector, a test contact for each line and an auxiliary test contact for each line, a motor magnet in said connector, a stepping relay for operating said magnet, circuit connections for operating said stepping relay by way of said auxiliarytest wiper and the auxiliary test contacts ofbusy called lines, a wiper connecting relay, and circuit connections for operating said wiper connecting relay by way of said test wiper and the test contact of an idle called line.

12. In a telephone system, a rotary connector, lines accessible to said connector divided into roups, means for directively opconnector to select a desired group of lines and for automatically operating said connector to select'an idle line in the selected group, a wiper connecting relay operated when an idle line is connected with, means in said connector for signalling the called line and for feeding talking current thereto, a release magnet for restoring said connector, and a circuit for said magnet controlled by said relay.

13. In a telephone system, a rotary connector, lines accessible to said connector divided into groups, means for directively op erating said connector to select a desired group of lines and for automatically operating said connector to select an idle line in the selected group, said operating means including a stepping magnet, a relay operated when an idle line is found to complete a'circuit for signalling the called line, and

a ring cut-ofi' relay, said signalling circuit including the said ring cut-off relay and the said stepping magne 1 Signed by me at New York, New York, this 7th day of July, 1920.

EMIL ,J'AcoBsEN. 

